package cn.tutu.blockchain.config;

import java.io.Serializable;
import java.util.Deque;
import java.util.LinkedList;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.shiro.cache.Cache;
import org.apache.shiro.cache.CacheManager;
import org.apache.shiro.session.Session;
import org.apache.shiro.session.mgt.DefaultSessionKey;
import org.apache.shiro.session.mgt.SessionManager;
import org.apache.shiro.subject.Subject;
import org.apache.shiro.web.filter.AccessControlFilter;
import org.apache.shiro.web.util.WebUtils;

import cn.tutu.blockchain.sysuser.entity.SysUser;

public class KickoutSessionControlFilter extends AccessControlFilter {

	private String kickoutUrl; // 踢出后到的地址
	private boolean kickoutAfter = false; // 踢出之前登录的/之后登录的用户 默认踢出之前登录的用户
	private int maxSession = 1; // 同一个帐号最大会话数 默认1
	private SessionManager sessionManager;
	private Cache<String, Deque<Serializable>> cache;

	public void setKickoutUrl(String kickoutUrl) {
		this.kickoutUrl = kickoutUrl;
	}

	public void setKickoutAfter(boolean kickoutAfter) {
		this.kickoutAfter = kickoutAfter;
	}

	public void setMaxSession(int maxSession) {
		this.maxSession = maxSession;
	}

	public void setSessionManager(SessionManager sessionManager) {
		this.sessionManager = sessionManager;
	} // 设置Cache的key的前缀

	public void setCacheManager(CacheManager cacheManager) {
		this.cache = cacheManager.getCache("shiro-activeSessionCache");

	}

	@Override
	protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue)
			throws Exception {
		// TODO Auto-generated method stub

		return false;
	}

	@Override
	protected boolean onAccessDenied(ServletRequest request, ServletResponse response) throws Exception {
		Subject subject = getSubject(request, response);
		System.out.println(subject.isAuthenticated());
		System.out.println(subject.isRemembered());
		if (!subject.isAuthenticated() && !subject.isRemembered()) {
			// 如果没有登录，直接进行之后的流程
			return true;
		}
		Session session = subject.getSession();
		SysUser user = (SysUser) subject.getPrincipal();
		if (null == user) {
			return true;
		}
		String nickName = user.getNickName();
		Serializable sessionId = session.getId();
		synchronized (this.cache) {
			// 读取缓存 没有就存入
			Deque<Serializable> deque = cache.get(nickName);

			if (null == deque) {
				deque = new LinkedList<Serializable>();
				cache.put(nickName, deque);
			}

			// 如果队列里没有此sessionId，且用户没有被踢出；放入队列
			if (!deque.contains(sessionId) && session.getAttribute("kickout") == null) {
				// 将sessionId存入队列
				deque.push(sessionId);
				// 将用户的sessionId队列缓存
				cache.put(nickName, deque);
			}

			// 如果队列里的sessionId数超出最大会话数，开始踢人
			while (deque.size() > maxSession) {
				Serializable kickoutSessionId = null;
				if (kickoutAfter) {
					// 如果踢出后者
					kickoutSessionId = deque.removeFirst();
				} else {
					// 否则踢出前者
					kickoutSessionId = deque.removeLast();
				}
				// 踢出后再更新下缓存队列 cache.put(username, deque);
				try {
					// 获取被踢出的sessionId的session对象
					Session kickoutSession = sessionManager.getSession(new DefaultSessionKey(kickoutSessionId));

					if (kickoutSession != null) {
						// 设置会话的kickout属性表示踢出了
						kickoutSession.setAttribute("kickout", true);
					}
				} catch (Exception e) {
					// ignore exception
					e.printStackTrace();
				}
			} // 如果被踢出了，直接退出，重定向到踢出后的地址

			if (session.getAttribute("kickout") != null) {
				// 会话被踢出了
				try {
					subject.logout();
				} catch (Exception e) {
					// ignore
					e.printStackTrace();
				}
				saveRequest(request);
				HttpServletRequest httpRequest = WebUtils.toHttp(request);
				if (isAjax(httpRequest)) {
					HttpServletResponse httpServletResponse = WebUtils.toHttp(response);
					httpServletResponse.sendError(500);
					return false;
				} else {
					WebUtils.issueRedirect(request, response, kickoutUrl);
					return false;
				}
			}
		}

		return true;
	}

	public Boolean isAjax(ServletRequest request) {
		String header = ((HttpServletRequest) request).getHeader("X-Requested-With");
		if ("XMLHttpRequest".equalsIgnoreCase(header)) {

			return Boolean.TRUE;
		}
		return Boolean.FALSE;
	}

}
